Heat treating container



March 1940- A. M. MILLER El Al. 2,192,648

HEAT TREATING CONTAINER Filed Au 15, 1938 Angus M. Miller Harvey h.Ltybtlc.

and

Patented Mar. 5, 1940 UNITED STATES,

:m-gmg e a HEAT TREATING oi T'AmR Angus M. Miller, Pleasant-Ridge,andHarveyH.

Lightle, Detroit, Mich, assignors to The Electro-Alloys Company, Elyria,Ohio, a corpora-,5

tion of Ohio Application August 13, 1938, Serial No. 224, 22

s Claims. (chess-'49) This invention relates to heat treating containerssuch as carburizing boxes and annealing I subjected to the heat of thefurnace. The heat is directed to the sides and ends of the box, to causeheating of the box,"the contained articles Y and the carburizing agent,until the articles are heated to a desired predetermined temperature,

whereupon the metal articles will absorbthe carburizing agent.

The effect of the temperature which-may reach from 1600 to 1800 F. is toadd to the carbon contents of the surface portion of the metal articles. After the carburizing operation, the boxes are then withdrawnfrom the furnace and cooled and the heat absorbed bythe box and theconktents becomes gradually dissipated. consequent 25k ly the boxes aresubjected to extreme variation,

in temperature andin former constructions, due

to the expansion and contraction of the walls of, the boxes, morparticularly the side walls, these Walls commonly become thermallywarped, or otherwise damaged. 1;

Also, in prior constructions there hasbeen difficulty caused by some ofthe metal articles placed in a box to be .carburized becoming heated tocarburizing temperatures more rapidly than 35. other articles includedin the box, and also the reverse condition, when some of the articlesare cooled more rapidly than other difierently disposed articles, withthe result that the articles are not uniformly carburized. We havedevised a carburizing box formed of cast metal and sheet' or plateconstructed to permit uniform distribution of heat to the interior ofthe box and reinforced so that a floating action of the plate formingthe side walls may occur due to temperature variation without danger ofpermanent distortion or fracture of the Walls. I It is an objectof ourinvention therefore to provide an improved carburizing box of ruggedconstruction whereby articles placed therein and subjected tocarburizing temperatures may be more uniformly subjected to suchtemperatures both during the heating and cooling period.

Another object of our invention is to provide an improved carburizingbox having relatively .a consideration of the description-and drawing 15thin walls formed of plate material of singlethickness reinforced in animproved manner.

Another object of'our invention is to provide an improved carburizingbox having side walls formed of relatively thin plate of heat. resistingmaterial reinforced inamanner to permit of a floating action of theplate responsive :to the temperature variation. I Another object of ourinvention is, .to provide an improved carburizing box which can. beeco-. nomically manufactured and assembled I Other objects of ourinvention and the invention itself willbecome increasingly apparentfromwherein i p 7 1 is a plan view of a. carburizing box formed inaccordance with our invention;

Fig. 2 is a front elevational view of the box of Fig. 1;

Fig. 3 is a Side elevational view ofthe box of Fi 1; w Fig. 4' is afragmentary sectional viewj-taken along the line 44 of Fig. 1; Fig. 5 isan enlarged fragmentaryview of a corner of the box illustrated in Fig. 2and Figs. 6, '7 and 8 arexplan, front elevational andend elevationalviews respectively of a portion-of a reinforcing element we mayemploywith the box illustrated in Figs. 1, 2 and 3. r v

Referring now to the drawing, and particularly to Figs. 1, 2 and 3, wehave" shown a preferred form of our invention wherein a single plate It;

,is bent into generally rectangular formand its; adjacent edges weldedor otherwise secured-to-' gether with rounded corner portions asindicated in Fig, 1 at l I is held in such form by corner elementsgenerally indicated at 12. I Ifdesired the plate It] may be formed ovalor round. The corner elements I2 are alike in construction and eachcomprises similarly formed upperand lower members [3 confrontinglydisposed and integrally secured "together generally centrally ofplate-i110 in any suitable manner as by welding. Eachof the members i3is of-arcuate'form' to conform to the contour of the corner portion H ofplate: II], the upper portion of the member being formed toprovide adepending inner flange l4 spaced from between to loosely receive the topand bottom portions of plate It.-

The members i3 are preferably provided with longitudinally extendingslots 5311-1311 permitting more efiicient heating of plate l0 anddecreasing the weight of the carburizing box. As best indicated in Fig.2, the wall l5 of member I 3 is extended as indicated at I! to provide acooperating outer flange for the inner flange I4.

Top and bottom reinforcing elements generally indicated at I8 areprovided between each of the corner elements I2, and the elements I8being preferably cast metal and of U-form in cross section. The elementsI8 arecut back at each endto provide a vertically extending face I9 andhorizontally extending arms 20-40, the depth of the elements at the endsbeing increased to form the arm 20. The reinforcing elements are adaptedto loosely engage the top and bottom portions of plate ID intermediatethe corner 'elements I2 and are maintained in place by the arms 20 beinghooked under the flanges I4 and I! of the corner elements I2. It will beunderstood that in assembling the carburizing box the reinforcingelements I8 are first placed in position and that the corner elementsare subsequently hooked over the corner portions of plate II] to lockthe reinforcing elements in assembled position by welding or otherwisesecuring the cooperating pair of members 13 together. The reinforcingelements I8 are not secured directly to plate It in any manner and thevertically extending faces I9 and arms 20 of the reinforcing elementsare spaced from the flanges I4 and I! of the corner elements I2 so thatthe reinforcing element I8 is permitted a limited floating action.

Thus, the side walls formed by the plate It may expand and contractunder thermal change to relatively alter the distance between cornerelements II without interference by the reinforcing elements 18 and atthe same time by providing a desired clearance between the top andbottom.

portion of plate I0 and the grooves 55 of the corner elements, the sidewalls may expand and contract in a vertical direction. The abovedescribed construction permits a full floating action between thecarburizing box side walls formed by the plate It, the corner elementsI2, and the reinforcing elements I8 while at the same time the cornerelements I2 and reinforcing elements I8 form a rugged cast metal framework for reinforcing the relatively thin plate side walls. Thus, thereis no danger of the plate side walls being permanently warped or bentout of a plane including the reinforcing elements I8 and at the sametime shocks which might be occasioned by superposing one loaded box onanother are largely absorbed by the corner elements I2;

We have shown the side walls of the carburizing box as being formed of asingle plate but it is understood that several plates may be usedandintegrally joined together so that each side wall may consist of adifferent plate.

Although we have shown and described a preferred form of our invention,we contemplate that numerous and extensive departures may be madetherefromv without departing from the spirit of our invention and thescope of the appended claims.

Having thus claim is:

described our invention, what we 1.' A heat treating containercomprising a sub stantially continuous one piece sheet metal wall benttogenerally tubular form, vertical elements having flanged ends providedwith confronting slots receiving top and bottom portions of the wall,and longitudinally slotted reinforcing elements loosely engaging top andbottom portions of the wall intermediate said vertical elements.

2. A carburizing box of generally rectangular form comprising sheetmetal side walls, corner elements having flanged ends provided withconfronting slots receiving the side walls, and reinforcing elementsextending intermediate the corner elements and interlocked therewith,the reinforcing elements being slotted to receive the side walls.

3. A carburizing box comprising side walls formed of plate material ofsingle thickness bent to form a generally rectangular tube, areinforcing frame loosely supporting the side walls and permitting afloating action of the side walls responsive to thermal change, saidframe comprising corner elements hooked over top and bottom cornerportions of the side walls, reinforcing elements telescoped over top andbottom portions of the side walls intermediate the corner elements, andmeans for loosely interlocking the reinforcing elements with the cornerelements.

4. A heat treating container comprising a tubular wall structure,reinforcing elements at the upper and lower edges of said tubular wallstructure and spaced from each other around the upper and lower edgesand loosely engaging the wall structure, and vertically extending cornerelements superposed over top and bottom corner portions of the tubularwalled structure and disposed between said first named elements andinterengaged therewith.

5. The method of forming heat treating containers which includes bendingplate material to form a generally rectangular tube having arcuatecorner portions, telescoping grooved reinforcing elements over top andbottom portions of the tube side walls intermediate the corner portions,hooking cooperating top and bottom corner elements over the tube cornerportions having portions engageable with the reinforcing elements,

and integrally joining the cooperating top and bottom corner elements toprovide a protective frame for the tube.

6. The method of forming heat treating containers which includes formingplate material into a tubular member, telescoping grooved reinforcingelements over top and bottom portions of the tube in spaced relation,hooking cooperating top and bottom reinforcing elements over theopposite edges of the tube, and between said telescoping groovedreinforcing elements and integrally joining the cooperating top andbottom elements to provide a protective frame for the tube.

ANGUS M. MILLER. HARVEY H. LIGHTLE.

